package com.yjkf.zh.admin.util;

import java.security.MessageDigest;

/**
 * 密码加密规则
 */
public class PasswordEncoder {

    private final static String[] hexDigits = {"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};

    private final static String MD5 = "MD5";

    private final static String SHA = "SHA";

    private Object salt;

    private String algorithm;

    public PasswordEncoder(Object salt){
        this(salt, MD5);
    }

    public PasswordEncoder(Object salt,String algorithm){
        this.salt = salt;
        this.algorithm = algorithm;
    }

    public String encode(String rawPass){
        String result = null;
        try {
            MessageDigest md = MessageDigest.getInstance(algorithm);
            //加密后的字符串
            result =byteArrayToHexString(md.digest(mergePasswordAndSalt(rawPass).getBytes("utf-8")));
        }catch (Exception ex){

        }
        return result;
    }

    /**
     * 密码匹配验证
     * @param encPass   密文
     * @param rawPass   明文
     * @return
     */
    public boolean matches(String encPass,String rawPass){
        String pass1 = ""+encPass;
        String pass2 = encode(rawPass);
        return pass1.equals(pass2);
    }

    private String mergePasswordAndSalt(String password){
        if(password == null){
            password = "";
        }

        if ((salt == null) || "".equals(salt)) {
            return password;
        } else {
            return password + "{" + salt.toString() + "}";
        }
    }

    /**
     * 转换字节数组为16进制字串
     *
     * @param b
     *            字节数组
     * @return 16进制字串
     */
    private String byteArrayToHexString(byte[] b) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++) {
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }

    /**
     * 将字节转换为16进制
     * @param b
     * @return
     */
    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n = 256 + n;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }
}
